1. Field of the Invention
The present invention relates to a washing machine transmission, more particularly to a washing machine transmission which performs a washing by rotating a pulsator in forward and reverse directions even if a driving source rotates in one direction only during a washing cycle, and which prevents an overloading of the driving source.
2. Description of the Prior Art
In general, various kinds of transmissions have been proposed for rotating the pulsator in forward and reverse directions during the washing cycle and for rotating a spin tub during a spin cycle.
The transmission of a fully automatic washing machine according to the prior art comprises a dual axle structure which is supported by bearings and has a washing output axle connected to a pulsator and a spin output axle connected to a spin tub. The transmission of the fully automatic washing machine only rotates the washing output axle clockwise and counterclockwise during the washing cycle and rotates the spin output axle along with the washing output axle in the same direction during the spin cycle by way of a connection with a clutch spring. The transmission comprises a one way clutch for transmitting power so that the spin output axle is rotated only in a spin rotating direction and is prevented from rotating in a reverse direction.
The transmission of the washing machine according to the prior art performs a washing by way of forward and reverse rotation of the driving source to thereby rotate the pulsator clockwise and counterclockwise during the washing cycle, and performs a spinning by way of rotation of the driving source to thereby rotate the pulsator and the spin tub in any one direction simultaneously during the spin cycle.
Accordingly, in the transmission of the washing machine according to the prior art, the driving source is rotated in forward and reverse directions to thereby rotate the pulsator, so that various problems such as an overload in the driving source and a shortening of the life cycle of the driving source have arisen.
U.S. Pat. No. 5,379,616 (issued to Sang-Chul Bae on Jan. 10, 1995) discloses a power transfer apparatus of a fully automatic washing machine which can perform a washing by rotating a washing means in forward and reverse directions during a washing cycle even though a driving source rotates only in a first direction, and which can perform a spinning when the driving source is rotated in a second direction to thereby rotate the washing means and the spin tub in the second direction, so an overload in the driving source can be prevented and the life of the driving source can be extended.
In Bae's Patent, the transmission, as illustrated in FIG. 1, comprises a driving shaft 40 with a connecting mechanism which has cases 7 and 9, a clutch means 54, a conversion member 30, gear arrangements 32, 41 and 42, a rack member 20, a guide unit 31, and a band brake 4. In Bae's transmission, when power is transmitted from the driving source (not shown) to driving shaft 40 so that driving shaft 40 rotates in the first direction during a washing, band brake 4 clutches a periphery of a transfer case member 60 so that the transfer case member 60 is prevented from rotating, and gear arrangements 32, 41 and 42 transmit a rotation of driving shaft 40 to the conversion member 30. The rack means 20 is rectilinearly reciprocated along a track of guide unit 31 formed on the conversion member 30 eccentrically from an axis of the conversion member 30. Thus, driven shaft 10 is rotated in forward and reverse directions by means of a gear 11 of the driven shaft 10 engaged with rack gear 21 of the rack member 20 so that the washing member (not shown) coupled with driven shaft 10 also is rotated in forward and reverse directions.
The driving source rotates in the second direction and band brake 4 releases a braking of transfer case member 60 during the spin cycle so that driving shaft 40 and spin tub shaft 62 connected to transfer case member 60 rotate in the same direction simultaneously, thereby performing the spinning.
In Bae's transmission, the driving source is rotated only in any one direction during the washing so that an overload in the driving source can prevented. But the transmission has a complex structure and the driving source substantially has different rotating directions during the washing and spinning cycles respectively.